Steering column switch with microswitches that has two operating positions and one neutral position system for cleaning windscreens

ABSTRACT

A steering column switch for motor vehicles comprises a base plate and first, second, and third identical microswitches placed onto the plate that are indirectly actuated by an operating lever through terminal links. The operating lever has a neutral position and two operating positions. The third microswitch that is assigned to the neutral position is arranged in a flat position. The terminal link actuating the third microswitch is arranged in a plane parallel to the base plate. A sampling roller prevents frictional losses during the actuation of the third microswitch via a control contour on the control lever.

BACKGROUND OF THE INVENTION

The invention pertains to a switch for motor vehicles which comprises apivoted operating lever, one pivoting position of which represents aneutral position that also has an assigned electrical state.

DE-OS 3,249,359 discloses a steering column switch, in which the left orright turn signals are respectively connected to a voltage source viasensitive microswitches if the operating lever is manually moved intothe two operating positions. In this particular switch, no circuit isclosed in the neutral position of the operating lever.

In this known steering column switch, the sensitive microswitches arerealized in the form of encapsulated circuit switches that are actuatedby the operating lever.

A similar switch with two sensitive microswitches that are realized inthe form of make contact elements and selectively actuated via theoperating lever is used as a mode selection switch in constructionmachines and tractors. In one operating position of the operating lever,the transmission is shifted into the forward mode, with the transmissionbeing shifted into the reverse mode when the operating lever is movedinto the other operating position. In such instances, it would bedesirable to close an additional circuit in the neutral position of theoperating lever which, for example, is looped into the starter circuitof an internal combustion engine.

The additional circuit that is closed in the neutral position of theoperating lever should be interrupted in both operating positions of theoperating lever so as to effectively prevent the internal combustionfrom starting in one of the operating positions that represent theforward mode and the reverse mode of the transmission.

DE-OS 3,623,979 discloses a suitable switch for this purpose thatfulfills its function with only two sensitive microswitches. However,the switches disclosed in this publication are relatively complicatedand have a comparatively large space requirement. In addition, theswitching contacts are not well protected, i.e., the switching contactsare easily affected by dirt and corrosion.

A similar switch is described in DE-OS 2,855,451.

An object of the invention consists of designing a switch with threeswitching positions in such a way that it can be inexpensivelymanufactured and that it is largely insensitive to environmentalinfluences.

SUMMARY OF THE INVENTION

This objective is attained with-a third encapsulated microswitch that isassigned to the neutral position and delivers the desired signal.

The operating lever must have a sufficient size in order to ensure itssimple handling, but the travel range of the microswitches available onthe market is very small. According to the invention, the operatinglever is made into a T-shape and can be selectively rotationally movedaround a pivoting axis passing through the lever in an area ofintersection of horizontal and vertical portions of the T-shape. Inorder to realize a precise switching function of the microswitches, theoperating lever does not directly act upon the actuating pin of thecorresponding microswitch, but rather indirectly via a terminal linkthat carries out the suitable power and directional transmission. Theoperating lever engages on the terminal links of the first and secondmicroswitches by the ends of its horizontal portion and acts on theterminal link of the third microswitch by the free end of its verticalportion, respectively.

Such a terminal link may be arranged on the end of a microswitch suchthat it can be independently turned. However, this predetermines a powerand directional transmission that is considered unsuitable for theactuation of a microswitch in the neutral position because only arelatively small angular movement is frequently available for theactuation of the switch. In order to ensure a precise switching functionin this respect, a pivotal axis for the third terminal link is arrangednormal to the plane of the base plate and a pivoted end of the thirdterminal link acts upon an actuating pin of the third microswitch. Thesefeatures make it possible to realize a relatively low spring constantwith respect to the contact between the terminal link and the operatinglever, and to actuate the actuating pin of the microswitch with acomparatively short travel of the terminal link.

In order to increase the travel of the operating lever that only passesthe actuating pin over a relatively short distance in the actuatingdirection of the actuating pin, the operating lever is provided with acontrol projection that engages on the third terminal link and actuatesthis terminal link during a pivoting motion of the operating lever.These features make it possible to hold the microswitch in the desiredactuating state in the small, limited switching positions of theoperating lever. This may, in principle, be realized by providing acontrol contour on the guide projection which acts upon the terminallink and controls the actuating pin via the terminal link.

In order to reduce the friction caused thereby and the resulting wear, asampling roller is arranged in rotatable fashion on the third terminallink in such a way that the sampling roller samples a control contourarranged on the operating lever control projection during the pivotingmotion of the operating lever. Due to these features forces exerted inthe longitudinal direction of the terminal link are reduced to aminimum, i.e., the operating lever can be operated very easily.

The microswitches are held between projections that protrude normallyfrom the base plate.

In order to additionally prevent the third microswitch from movingopposite to the installation direction, the microswitch is held on thebase plate by a projection latch connection where a latching tab isprovided that engages behind a lateral edge of the microswitch.

An additional holding projection engages the third microswitch into athrough opening therein.

This additional holding projection may be hot-deformed on the endthereof that protrudes beyond the through opening in such a way that itengages behind an edge of the through opening.

There are provided windows in the base plate, and electrical connectionsof the microswitches lie above the windows, with connecting lines thatlead to the electrical connections extending through the windows fromunderneath the base plate.

One embodiment of the invention is described below with reference to thefigures.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures show:

FIG. 1 a side view of a sectioned operating lever;

FIG. 2 a top view of the operating lever according to FIG. 1;

FIG. 3 a side view of the switch according to the invention which isrealized without an operating lever, and

FIG. 4 a top view of the switch according to FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

The operating lever 1 is arranged on the base plate 4 (FIG. 3, 4) withthe aid of two pivot pins 2,3 such that said operating lever can beturned relative to the base plate. In FIGS. 1 and 2, the operating levercomprises an extension, which is not shown, on the left side of the lineof section. The operating lever 1, which is made into a T-shape, can bepivoted about a pivoting axis (not shown) passing through the pivot pins2, 3 in an area of intersection of horizontal and vertical portions ofthe T-shape by means of this extension. In addition, the operating lever1 is provided with a sleeve 5 that serves for accommodating a latchelement. In this case, the latch element is conventionally supported ona contour that is arranged stationary with respect to the base plate 4.Consequently, the latch element can be latched into three angularpositions that correspond to the two operating positions and the neutralposition of the operating lever. In the top view according to FIG. 2,the operating lever 1 is shown in its neutral position. The operatinglever is moved into its two operating positions by pivoting its frontend 6 about the pivot pins 2 and 3 in FIG. 2.

The operating lever 1 carries two lateral wings 7, 8, of its horizontalportion that comprise two actuating surfaces 9,10. These actuatingsurfaces follow the pivoting motion of the operating lever. The baseplate 4 in FIGS. 3 and 4 is equipped with three microswitches 11, 12, 13which are encapsulated and identically designed. In this case, the twocuboid microswitches 11 and 13 are arranged in upright fashion, with themicroswitch 12 being arranged such that it lies on the base plate 4. Thehousings of the microswitches 11 and 13 are provided with two opposingprojections, in which a bearing fork 15 of a terminal link 16 isarranged in pivoted fashion. The bearing fork 15 is supported in thepivoted fashion by bearing bolts 14. The two terminal links 16 act uponactuating pins 17 that extend into the housings of the microswitches11-13 and initiate the desired switching processes when they are movedin their longitudinal direction.

The electrical connections 18 of the microswitches, which, for example,are connected to an electric line 19, are shown on the side of themicroswitches 11-13 that is situated opposite to the actuating pin 17.

The microswitches 11 and 13 are held by side walls of the base plate.These microswitches are clamped into the bordered interior of the baseplate by means of clamping connections. The side walls 20 are relativelylow in comparison to the height of the microswitches. The holdingmechanism of the microswitches also includes high side walls 22 thatsimultaneously ensure a mechanical shielding of the electricalconnections 18 and support the microswitches 11, 13 in the plane of thebase plate 4, namely in the direction that is not blocked by the sidewalls 20 and a circumferential edge 23. A bearing block 25 protrudesfrom the base plate 4. A bearing fork 26 is supported in pivoted fashionby two bearing bolts 24 that protrude from the aforementioned bearingblock.

The bearing fork 26 forms the rotatably supported end of a secondterminal link 27 that acts upon the bearing pin 17 of the microswitch12. A second bearing fork 28 is arranged on the end of the terminal link27 which is situated opposite to the bearing fork 26. A sampling roller29 is supported in rotatable fashion in the second bearing fork. Theflat-lying microswitch 12 is fastened onto the base plate 4 by means oflatching arms 30,31 that engage on the surface of the microswitch 12with their tabs 32 and retain the microswitch relative to the baseplate. Holding projections 39 that protrude into the microswitch viathrough-openings 33 additionally serve for fastening the lyingmicroswitch 12. After installing the microswitch 12, the upper end ofthe holding projections may be flattened such that said holdingprojections are able to prevent the microswitch from being lifted offthe base plate.

Within the region of the connections 18, the base plate is provided withwindows 41, 42, 23. As described previously, an electric line 19 (FIG.3) that leads from a connection 18 to the on-board network of a motorvehicle or to a sink extends through these windows.

In the assembled condition, the operating lever 1 is arranged such thatit can be pivoted relative to the base plate 4 about its pivot pins 2,3.In this case, the pivot pin 3 engages into a cylindrical pot 44 on thebase plate 4. The bearing point for the pivot pin 2 which is situated inthe housing of the switch is not visible in the figures.

The operating lever that is arranged on the base plate 4 in pivotedfashion engages on the terminal links 16 with the actuating surfaces9,10 of the lateral wings 7, 8. In FIG. 3, these terminal links extendtransversely from the lower right to the upper left.

In the installed condition of the operating lever 1, the free travel ofthe terminal link is limited to such a degree that a comparatively smalltravel range of the operating lever must suffice for actuating bothmicroswitches 11, 13.

A control projection 46 that carries an essentially V-shaped controlcontour 47 is fastened to the lower end of the vertical portion theoperating lever (see FIG. 1). When pivoting the operating lever, thecontrol contour 47 passes a sampling roller 29 that is prestressed inthe direction of the contour springs and arranged within the region ofits neutral position such that said roller and consequently thecorresponding end of the second bearing fork 28 are moved in accordancewith the control contour 47 (comparatively V-shaped). This motionresults in a slight pivoting motion about the bearing bolt 24.

The free end of the second bearing fork that is moved toward the rightduring the passage of the control contour 47 according to FIG. 4consequently presses the actuating pin 17 of the microswitch 12 into themicroswitch and actuates the switching contact of the microswitch in thedesired fashion. In other words, when the operating lever 1 is in itsneutral position, the contour 47 acts through the roller 29 and terminallink 27 onto the pin 17, thus activating the third microswitch 12 andmoving it into an operating microswitch position. On the other hand,when the operating lever is being rotated and thus leaves its neutralposition, the contour 47 exerts no pressure anymore on the pin 17, whichresults in releasing the microswitch 12 and deactivating it into an idlemicroswitch position.

What is claimed is:
 1. A switch for motor vehicles, comprising: a baseplate; a manually activated T-shape operating lever that can beselectively rotatingly moved around a pivoting axis passing through saidoperating lever in an area of intersection of horizontal and verticalportions of said T-shape from a neutral lever position into either afirst or a second operating lever position; a first and a secondencapsulated microswitch placed in an upright fashion onto said baseplate, said first and a second encapsulated microswitch each having anidle microswitch position and an operating microswitch position; saidfirst and said second microswitches being adapted to be activated bysaid operating lever, when it moves from said neutral lever positioninto said first or said second operating lever position respectively, tothus move from said idle microswitch position into said operatingmicroswitch position; a third encapsulated microswitch placed in a lyingposition onto said base plate; said third microswitch being adapted tobe activated by said operating lever in said neutral lever position,wherein a terminal link is provided for operating each of said first andsaid second microswitches, said operating lover engaging on eachterminal link with a corresponding end of said horizontal portion ofsaid T-shape thereof during said rotating motion thereof, to therebymove the corresponding microswitch into its operating microswitchposition, and wherein a third terminal link is provided for said thirdmicroswitch, and said operating lever is provided with a controlprojection at a free end of said vertical portion of said T-shapethereof, said control projection engaging on said third terminal link insaid neutral lever position to thereby activate said third microswitch,whereas, when moving with said operating lever during said rotatingmotion thereof from said neutral lever position, said control projectiondisengages from said third terminal link and thus deactivates said thirdmicroswitch, whereby said third microswitch moves into said idlemicroswitch position.
 2. The switch according to claim 1, wherein apivoting axis of said third terminal link extends parallel to saidpivoting axis of said operating lever.
 3. The switch according to claim1, wherein a sampling roller is arranged in rotatable fashion on saidthird terminal link in such a way that said sampling roller samples acontrol contour arranged on said control projection during said pivotingmotion of said operating lever.
 4. The switch according to claim 1,wherein a pivoting axis of a third terminal link is arranged normal to aplane of said base plate and a pivoted end of said third terminal linkacts upon an actuating pin of said third microswitch.
 5. The switchaccording to claim 1, wherein said third microswitch is held betweenprojections that perpendicularly protrude from said base plate.
 6. Theswitch according to claim 5, wherein at least one projection of saidprojections is provided with a latching tab that engages behind alateral edge of said third microswitch and thus holds said thirdmicroswitch on said base plate.
 7. The switch according to claim 1,wherein a holding projection engages into an opening of said thirdmicroswitch.
 8. The switch according to claim 7, wherein said holdingprojection is hot-deformed on its end that protrudes beyond said openingin such a way that it engages behind an edge of said opening.